Call hold signaling

ABSTRACT

One or more elements in a telecommunications network ( 10, 10 ′ and  10 ″) receive a call hold-initiating message when a first party places a second party to the call on hold, and in doing so, triggers a call hold event in the network. In response to the call hold-initiating message, the network element may take one or more actions, including releasing one or more network resources and/or providing a service to the second party during the period the call remains on hold. Upon resumption of the call, the network will re-acquire the resources that had been previously released.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority to co-pendingU.S. patent application Ser. No. 11/184,126, filed Jul. 19, 2005, nowallowed, which will issue as U.S. Pat. No. 7,248,683 on Jul. 24, 2007,which is a continuation of U.S. patent application Ser. No. 10/078,685,filed Feb. 19, 2002, which issued as U.S. Pat. No. 6,925,161 on Aug. 2,2005. The aforementioned related patent applications are hereinincorporated by reference.

TECHNICAL FIELD

This invention relates to a technique for propagating signalinginformation within a telecommunications network.

BACKGROUND ART

Technical advances in the development of telecommunications networksallow telephone subscribers to enjoy a variety of telecommunicationsservices. For example, subscribers may now subscribe to a call holdfeature whereby one party to a call can temporarily place that call onhold to accept another call. To activate this service, the party seekingto place the call on hold (hereinafter, the “holding party”) does so bysignaling an Ingress network switch, typically by actuating the switchhook on the telephone set.

Many business and other entities that receive large volumes of calls viaone or more local or a toll-free numbers employ a private branchexchange (PBX) often in concert with an automatic call director toenable queuing of incoming calls for answer by an available agent. Uponanswering the call, the attendant may need to place the calling party onhold to access a record or consult with a supervisor. After performingthe required task, the attendant will then return to the call.

Currently, no mechanism exists for alerting network element(s) of a callbeing placed on hold. Thus, telecommunications carriers lack the abilityto offer the party on hold (hereinafter, the “held party”) a service ofinterest during the hold period. The absence of any mechanism foralerting network elements of the call being placed on hold incursanother disadvantage. Typically, a telecommunications carrier willtypically commit certain resources within its network in order tocomplete a call between the calling and called party. Usually, suchresources remain committed for the duration of the call and only uponcall completion do such resources become available for other calls.Thus, such resources remain committed even during the interval in whicha call remains on hold. Unfortunately, there currently exists nomechanism for enabling such network resources to know when a call hasbeen placed on hold to allow their release and re-use during the holdperiod.

Thus, there is a need for a technique for propagating a signal amongelements within a telecommunications network to alert each element whena call is placed on hold.

BRIEF SUMMARY OF THE INVENTION

Briefly, in accordance with a preferred embodiment, the presentinvention provides signaling within a telecommunications network foralerting one or more network elements when the holding party has placeda call on hold and when that party has taken the call off hold. Suchsignaling allows the network to re-use network resources during theperiod the call is on hold, as well as the ability to offer one or moreservices to the held party during the interval the call is held. Themethod commences upon the receipt in the network of a call hold eventresponsive to the holding party placing the call on hold. The call holdevent may take the form of a switch hook or other signal from theholding party to signal the network that it should place the call onhold. Alternatively, the call hold event may comprise a signal from apiece of customer premises equipment (e.g., a Private Branch Exchange)that has itself placed the call on hold. In response to detecting a callhold event, the network generates a call hold-initiating messagepropagated to at least one network element. In response, the elementreceiving the call hold-initiating message takes one or more actionswhile the call is on hold. The action taken by the network element mayinclude releasing a resource from the call on hold. Alternatively, or inaddition to releasing the resource, the network element, upon receivingthe call hold-initiating message, may prompt the held party to selectone or more services while the call is on hold. Once the holding partyhas returned to the call, the resources needed for the call arereconnected and the service offered to the held party is terminated.

BRIEF SUMMARY OF THE DRAWINGS

FIG. 1 depicts a block schematic diagram of a first embodiment of atelecommunication network architecture for propagating signalinginformation indicative of a call hold event to one or more networkelements in accordance with the invention;

FIG. 2 depicts in flow chart form the steps associated with propagatingsignaling information in response to a call hold event and a callresumption event in the network of FIG. 1;

FIG. 3 depicts a block schematic diagram of a second embodiment of atelecommunication network architecture for propagating signalinginformation indicative of a call hold event to one or more networkelements in accordance with the invention; and

FIG. 4 depicts a block schematic diagram of a third embodiment of anetwork architecture for propagating signaling information indicative ofa call hold event to one or more network elements in accordance with theinvention.

DETAILED DESCRIPTION

FIG. 1 depicts a block schematic diagram of a first embodiment of atelecommunications network architecture 10 for propagating signalinginformation to one or more network elements of a call hold event inaccordance with the invention. A call hold event occurs in response to aholding party placing a call on hold. In the illustrated embodiment ofFIG. 1, the network architecture 10 takes the form of a Public SwitchedTelephone Network (PSTN) and includes three separate networks 12, 14,and 16 interconnected to each other by bearer and signaling paths 17 and18, respectively. The networks 12 and 16 comprise Local Exchange Carrier(LEC) networks that provide local telephony service (dial tone) tosubscribers. As shown in FIG. 1, the LEC network 12 includes a publicswitch 19 ₁ that provides local telephone service to an individualsubscriber 20. In a similar manner, the LEC network 16 includes a publicswitch 19 ₂ that serves an individual subscriber 22 as well as a callcenter PBX 23 coupled to which is at least one, and typically, aplurality of agents 24 (only one of which is shown). Note that each ofthe public switches 19 ₁ and 19 ₂ could each serve a plurality ofindividual subscribers and call center PBXs.

The network 14 connects the LEC networks and serves to route callsbetween them. For that reason, the network 14 typically bears thedesignation of an Inter-Exchange Carrier (IXC) network and is bestexemplified by the AT&T IXC network. Situated within the IXC network 14is at least one toll switch 25 for routing a call received from one ofthe LEC networks 12 and 16 that is destined for the other LEC network.Typically the network 14 may include a plurality of interconnected tollswitches. In addition to the toll switch(es) 25, the IXC network 14 alsoincludes at least one Service Control Point/Service Node (SCP/SN) 26that generally takes the form of a database containing instructions forthe toll switch(es) for handing calls that requiring special treatment.Also, the IXC network 14 includes at least one Intelligent Peripheraldevice (IP_(e)) 28 that serves to collect digits and/or provideannouncements in connection with providing various services. Althoughnot shown, each of the LEC networks 12 and 16 may also include one ormore intelligent peripherals.

FIG. 2 illustrates in flow chart form the steps of the method of theinvention for propagating signaling information to one or more networkelements in the network architecture of FIG. 1 in response to a callhold event. Initially, a call starts within the network architecture 10during Step 102 of FIG. 1 when a calling party, say subscriber 20 ofFIG. 1 calls a called party, say subscriber 22 or the call center 23,both of FIG. 1. After call set-up, one party (i.e., the “holding party”)may choose to place the other party on hold. To that end, the holdingparty initiates a call hold event (Step 104 of FIG. 2). An individualsubscriber (e.g., one of subscribers 20 and 22) may place the otherparty on hold by signaling the subscriber's public switch (i.e., acorresponding one of public switches 19 ₁ and 19 ₂, respectively) toplace the call on hold by sending a flash hook. A call center (e.g.,call center PBX 23) may itself place the call on hold. Under suchcircumstances, the call center PBX 23 notifies its local switch (i.e.,switch 19 ₂) that the call center PBX has placed the call on holdtypically via a PRI/Q.931 signal.

In response to a call hold event, the network architecture 10 of FIG. 1generates a call hold-initiating message (step 106 of FIG. 2). Inpractice, the public switch that has placed the call on hold, or thatserves a call center PBX 23 which itself has placed the call on hold,will generate the call hold-initiating message and will propagate thatmessage, typically in the form of an SS7 signal, to one or more otherelements via the signaling trunks 18 (e.g., an SS7 signaling trunk) ofFIG. 1 during step 108 of FIG. 2. In response to the callhold-initiating message, the network element(s) receiving the messagewill take one or more actions. For example, in response to the call holdinitiating message, one or more toll switches 25 in the IXC network 14may release one or more resources from the call, such as IP_(e) 28 ofFIG. 1 during step 110 of FIG. 2. Other elements in one or both the LECnetworks 12 and 16 could also release one or more resources in responseto receipt of the call hold-initiating message.

In addition, or as an alternative to releasing resources, an element,such as the Intelligent Peripheral 28 that receives the callhold-initiating message may offer certain services (options) to the heldparty during step 112 of FIG. 2. For example, the held party couldreceive a menu of various audio messages during the holding period. Suchmessages could include news sources, stock quotes or even advertising orconsumer surveys, which if listened to by the subscriber could afford alower charge for the call or other benefit. After the offering the heldparty a menu of choices during step 112, a check is made during step 114of FIG. 2 whether the subscriber has made a selection. Step 112 iscontinually re-executed until a time out interval is detected duringstep 116. Assuming the held party has selected the desired serviceduring step 114, then that party receives that service during step 118of FIG. 2. With the network architecture of FIG. 1, the held partyreceives the service over a Plain Old Telephone Service (POTS) link.Note that the held party may finish receiving a first service before theholding party returns to the call. Under such circumstances, the heldparty could once receive the option to select another service, thusrepeating step 118.

Following step 118 (or following the time out interval determined duringstep 116), a check is made whether the holding party has returned to thecall during step 120. Upon returning to the call, the holding partyinitiates a call release event in a manner analogous as the call holdevent. Thus, an individual subscriber will send a flash hook to thecorresponding public switch to take the call off hold. The call centerPBX that had previously placed the call on hold, upon taking the calloff hold will notify the corresponding public switch of the call goingoff hold. Responsive to receipt of the call release event, the publicswitch serving the holding party generates a hold-releasing message forpropagation to one or more other elements in the networks 12, 14, and16. The return of the holding party to the call prompts a notificationto the held party during step 124 of FIG. 2, whereupon a check is madeon a repeated basis whether the held party is available during step 126.If, after a prescribed interval, the held party fails to becomeavailable, then a determination is made whether the current held party'saction can be terminated. If not, then the original call (the call beingheld) should be terminated along with the call hold during step 128. Ifthe held party's action can be terminated, then the hold is lifted, andnetwork resources are re-acquired (step 130) whereupon the original callis resumed during step 132. Once the held party does become available,the resources need to resume the call are re-acquired, if previouslyreleased, and applied to the call during step 130 of FIG. 2. Uponresumption of a call, any network resources that had been previouslyreleased need to be recovered. To that end, a signal indicative of theresumption of the call now propagates through the networks. Suchsignaling may include an indication that this is a resumed call—asopposed to a new call—so that priority treatment is given to allocatingthe needed resources. Thereafter, the call between the holding party andthe held party resumes during step 132.

The call hold signaling method of the invention, although describedabove in connection with the Public Switched Telephone Network of FIG. Imay also be practiced using a hybrid network which provides thesubscribers with a data connection, and in particular, an IP connection.FIG. 3 shows such a hybrid telecommunications network architecture 10′that includes the PSTN elements of FIG. 1 shown in FIG. 3 with likereference numbers. The network architecture 10′ includes a plurality ofIP devices 50 ₁, 50 ₂ and 50 ₃ typically, although necessarily, personalcomputers or the like, associated with the subscribers 20 and 22 and theagent 24, respectively. The IP device 50 ₁ enjoys a connection to afirst IP network 54 whereas the IP devices 50 ₂ and 50 ₃, along with thecall center PBX 23, enjoy a connection to a second IP network 56. BothIP networks 54 and 56 have a link to the SCP/SN 26. Note that a singleIP network (not shown) could serve all of the IP devices 50 ₁-50 ₃, aswell as the call center PBX 24 and the SCP/SN.

The hybrid network 10′ of FIG. 3 advantageously allows the subscribers20 and 22 and the agent 24 to receive a call hold notification as wellas to offer one or more services in connection with the call hold event,via a corresponding one of the IP devices 50 ₁, 50 ₂ and 50 ₃,respectively, when a party to the call has placed the subscriber/agenton hold. U.S. patent applications Ser. Nos. 09/428,363 filed Oct. 27,1999 and 09/801,562, filed Mar. 8, 2001, both assigned to AT&T, and bothincorporated by reference herein, describe mechanisms for providing callevent notification on an IP device in response to a call launched thoughone of the public switches 19 ₁ and 19 ₂ for delivery as a POTS (PlainOld Telephone Service) call to another public switch. Using suchmechanisms, the SCP/SN 26, in response to a call hold event received inthe network 14, would forward such a notification to the held party viaan associated one of the IP networks 54 and 56 for delivery on acorresponding IP device. Additionally, the SCP/SN 26 could provide theheld party via a corresponding IP device with a menu of servicesavailable to the held party during the call hold interval, including theservices previously discussed in connection with step 118 as well asmultimedia services, including providing the held party with videoinformation. In response to the selection, the held party could receivethe service on the IP device via an IP connection.

The network architecture 10′ can also provide a call hold notification,as well as provide menu options to the held party for call launched as aVoice over Internet Protocol (VoIP) call from one of the IP devices fordelivery to a subscriber/call center served by a public switch.Alternatively, the network architecture 10′ of FIG. 3 can provide callhold notification and menu options to the held party where the callinitiated from an IP device and terminated on an IP device with allcommunications through the IP network(s).

FIG. 4 depicts a second hybrid network architecture 10″ that shareselements in common with the hybrid architecture 10′ of FIG. 3 so likereference numbers depict like elements. With the hybrid networkarchitecture 10″ of FIG. 4, the subscriber 20 receives traditionalservice (POTS) from the public switch 19 ₁ at its Customer PremisesEquipment and also receives always-on IP service via DSL or cable frompacket network 54′. For example, today's technology allows a singleLocal loop to support a baseband PSTN line with lifeline capabilities,two DSL based packet voice connections that are connected to the publicswitch 19 ₁ for PSTN features, and a DSL connection. The call holdsignal can be translated at the subscriber's CPE to IP on the DSLconnection and be associated with any of the “PSTN” lines. This is anexemplary use of integrated PSTN/DSL technology. If the subscriber's CPElacks this capability, then the subscriber would need a caller ID-likebox, as discussed in U.S. patent application Ser. No. 09/801,562,incorporated by reference herein.

The foregoing describes a technique for propagating signalinginformation indicative of a call hold event and a call resumption eventto one or more elements in a telecommunications network architecture.

The above-described embodiments merely illustrate the principles of theinvention. Those skilled in the art may make various modifications andchanges that will embody the principles of the invention and fall withinthe spirit and scope thereof.

1. An apparatus for propagating signaling information in acommunications network to alert at least one element of a call holdevent when a first party to a telephone call with at least a secondparty places the call on hold, comprising: means for receiving in thenetwork a call hold event in response to the first party placing thecall on hold; and means for generating a call hold-initiating signal inresponse to receipt of the call hold event and propagating said callhold-initiating signal to at least one network element.
 2. The apparatusof claim 1, further comprising: means for taking an action while thecall remains on hold.
 3. The apparatus of claim 2, wherein the actiontaken comprises releasing at least one network resource associated withthe call while the call remains on hold.
 4. The apparatus of claim 3,further comprising: means for re-acquiring the at least one networkresource associated with the call once the first party returns to thecall.
 5. The apparatus of claim 4, further comprising: means foraffording priority treatment for re-acquisition of resources for aresumed call.
 6. The apparatus of claim 2, wherein the action takencomprises providing a service to the second party while the second partyremains on hold.
 7. The apparatus of claim 6, wherein the action takenfurther comprises providing the second party a menu of service choices.8. The apparatus of claim 7, wherein the service choices include atleast one of: (a) receiving news, (b) receiving a stock quote, (c)receiving an advertising or consumer survey, and (d) receiving videoinformation.
 9. The apparatus of claim 8, wherein the second partyreceives a benefit for listening to the advertising or responding to theconsumer survey.
 10. The apparatus of claim 9, wherein the benefitreceived by the second party comprises a lower charge for the call. 11.The apparatus of claim 6, wherein the second party receives the serviceover a Plain Old Telephone Service (POTS) link.
 12. The apparatus ofclaim 6, wherein the second party receives the service on an InternetProtocol device over an Internet Protocol link.
 13. The apparatus ofclaim 1, wherein the call hold event is received in the network from anInternet Protocol device in connection with a Voice over InternetProtocol (VoIP) call originated from the first party.
 14. The apparatusof claim 13, wherein the call hold-initiating signal is an SS7 signalgenerated in accordance with the call hold event received from theInternet Protocol device.
 15. An apparatus for propagating signalinginformation in a communications network to alert at least one element ofa call hold event when a first party to a telephone call with at least asecond party places the call on hold, comprising: means for receiving inthe network a call hold event in response to the first party placing thecall on hold; means for generating a call hold-initiating signal inresponse to receipt of the call hold event and propagating the callhold-initiating signal to at least one network element; means for takinga first action while the call remains on hold; means for receiving acall resumption-event in response to a first party taking the call offhold; means for generating a call resumption-initiating signal inresponse to receipt of the call resumption event and propagating thecall resumption-initiating signal to at least one network element; andmeans for taking a second action once the call is taken off hold. 16.The apparatus of claim 15, wherein the first action taken comprisesreleasing at least one network resource associated with the call whilethe call remains on hold.
 17. The apparatus of claim 16, wherein thesecond action taken comprises re-acquiring the at least one networkresource associated with the call once the first party has taken thecall off hold.
 18. The apparatus of claim 15, wherein the first actiontaken comprises providing a service to the second party while the secondparty remains on hold.
 19. The apparatus of claim 18, wherein the firstaction of providing a service comprises providing the second party amenu of service choices.
 20. A method for propagating signalinginformation in a communications network to alert at least one element ofa call hold event when a first party to a telephone call with at least asecond party places the call on hold, comprising the steps of: receivingin the network a call hold event in response to the first party placingthe call on hold; and generating a call hold-initiating signal inresponse to receipt of the call hold event and propagating the callhold-initiating signal to at least one network element.